| 5/5/18 |
Chicago Cubs signed free agent CF Rafael Herrera to a minor league contract. |
| 5/5/18 |
Chicago Cubs signed free agent C Malcom Quintero to a minor league contract. |
| 5/5/18 |
Chicago Cubs signed free agent C Pablo Aliendo to a minor league contract. |
| 5/7/18 |
Chicago Cubs placed RHP Yu Darvish on the 10-day disabled list retroactive to May 5, 2018. Parainfluenza virus |
| 5/7/18 |
Chicago Cubs optioned RHP Luke Farrell to Iowa Cubs. |
| 5/7/18 |
Chicago Cubs recalled RHP Cory Mazzoni from Iowa Cubs. |
| 5/8/18 |
Chicago Cubs placed RF Jason Heyward on the 7-day disabled list. Concussion protocol |
| 5/8/18 |
Chicago Cubs optioned RHP Cory Mazzoni to Iowa Cubs. |
| 5/8/18 |
Chicago Cubs signed free agent LF Lane Adams to a minor league contract. |
| 5/8/18 |
Chicago Cubs recalled 2B David Bote from Iowa Cubs. |
| 5/8/18 |
Chicago Cubs recalled LHP Rob Zastryzny from Iowa Cubs. |
| 5/8/18 |
Chicago Cubs recalled RHP Jen-Ho Tseng from Iowa Cubs. |
| 5/9/18 |
Chicago Cubs optioned LHP Rob Zastryzny to Iowa Cubs. |
| 5/9/18 |
Chicago Cubs optioned RHP Jen-Ho Tseng to Iowa Cubs. |
| 5/9/18 |
Chicago Cubs selected the contract of RHP Justin Hancock from Iowa Cubs. |
| 5/9/18 |
Chicago Cubs recalled RF Mark Zagunis from Iowa Cubs. |
| 5/14/18 |
Chicago Cubs signed free agent SS Pedro Martinez to a minor league contract. |
| 5/14/18 |
Chicago Cubs signed free agent SS Christhian Espinal to a minor league contract. |
| 5/15/18 |
Chicago Cubs activated RHP Yu Darvish from the 10-day disabled list. |
| 5/15/18 |
Chicago Cubs optioned RF Mark Zagunis to Iowa Cubs. |
| 5/16/18 |
Chicago Cubs placed RF Jason Heyward on the 10-day disabled list. Concussion. |
| 5/17/18 |
Chicago Cubs optioned 2B David Bote to Iowa Cubs. |
| 5/17/18 |
Chicago Cubs recalled Randy Rosario from Iowa Cubs. |
| 5/18/18 |
Chicago Cubs activated RF Jason Heyward from the 10-day disabled list. |
| 5/18/18 |
Chicago Cubs optioned LHP Randy Rosario to Iowa Cubs. |
| 5/19/18 |
Chicago Cubs recalled LHP Randy Rosario from Iowa Cubs. |
| 5/20/18 |
Chicago Cubs optioned LHP Randy Rosario to Iowa Cubs. |
